Reaktion #51701

Reaktionsgleichung

3,5-dibromopyridine

toluene

3-thiopheneboronic acid

sodium carbonate

→

purple oil

5-(3-Thienyl)-3-bromopyridine

Lösungsmittel

water

water

ethyl alcohol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter cooling to room temperature
2. 2
   Extraktionextracted with ethyl acetate (2×200 mL
3. 3
   TrocknenThe combined organic phases were dried with MgSO4
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated by rotary evaporation

Vorschrift

Under a nitrogen atmosphere, a mixture of 3,5-dibromopyridine (5 g, 21 mmol), distilled water (35 mL), toluene (140 mL), ethyl alcohol (35 mL), 3-thiopheneboronic acid (2.8 g, 22 mmol), sodium carbonate (4.67 g, 44.1 mmol) and tetrakis(triphenylphosphine)palladium (1.22 g, 1.05 mmol) were stirred. This black suspension was heated at 75° C. for 20 h. After cooling to room temperature, the mixture was diluted with distilled water (200 mL) and extracted with ethyl acetate (2×200 mL, then 100 mL). The combined organic phases were dried with MgSO4, filtered and concentrated by rotary evaporation, producing 17 g of a purple oil. Purification by column chromatography on silica gel, using cyclohexane:ethyl acetate (95:5) as eluent, afforded 2.9 g (58%) of white crystals, mp 58° C.

Quelle